If Firefox can't access a secure site (one that starts with https:) you will see an error page with the heading, Secure Connection Failed and a message about the error. This article will describe some of these error messages. If you don't see this heading, see Error loading web sites.

Table Of Contents

• SSL protocol has been disabled
• Certificate warnings
• Certificate will not be valid until (date)
• Certificate is only valid for (site name)
• The certificate is not trusted because it is self signed
• The certificate contains the same serial number as another certificate
• Bypassing the warning

SSL protocol has been disabled

If you see this error, see Firefox cannot connect securely because the SSL protocol is disabled.

Certificate warnings

Firefox uses certificates on secure websites to ensure that your information is being sent to the intended recipient and can't be read by eavesdroppers.

Certificate will not be valid until (date)

This error can occur if your computer clock has the wrong date, in which case the date given in the error message will be in the past. To fix the problem, set your system clock to today's date and time (double-click the clock icon on the Windows Taskbar).

Certificate is only valid for (site name)

This error is telling you that the certificate sent to you by the site is actually for another site. While anything you send would be safe from eavesdroppers, the recipient may not be who you think it is.

A common situation is when the certificate is actually for a different part of the same site. For example, you may have visited https://example.com, but the certificate is for https://www.example.com. In this case, if you access https://www.example.com directly, you should not receive the warning.

The certificate is not trusted because it is self signed

or

Self-signed certificates make your data safe from eavesdroppers, but say nothing about who the recipient of the data is. This is common for intranet websites that aren't available publicly.

The certificate contains the same serial number as another certificate

This error alerts you to the fact that the certificate the page you're visiting uses has a serial number identical to one you've already accepted. This warning cannot be bypassed using the method below. For more information and for instructions on how to work around this message, see the Certificate contains the same serial number as another certificate article.

Bypassing the warning

You can tell Firefox to bypass these certificate warnings. You should only bypass the warning if you're sure that the site is legitimate. Legitimate public sites will not ask you to do this. An invalid certificate can be an indication of a web page that will defraud you or steal your identity.

1. On the warning page, click Or you can add an exception....
2. Click Add Exception.... The Add Security Exception dialog will appear.
3. Click Get Certificate.
4. Read the text describing the problems with this site.
5. Click Confirm Security Exception if you want to trust the site.